US8300519B2 - Method and device for crosstalk evaluation and communication system comprising such device - Google Patents

Method and device for crosstalk evaluation and communication system comprising such device Download PDF

Info

Publication number
US8300519B2
US8300519B2 US12/602,253 US60225308A US8300519B2 US 8300519 B2 US8300519 B2 US 8300519B2 US 60225308 A US60225308 A US 60225308A US 8300519 B2 US8300519 B2 US 8300519B2
Authority
US
United States
Prior art keywords
crosstalk
eff
network component
fext
far
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US12/602,253
Other versions
US20100135374A1 (en
Inventor
Werner Kozek
Josef Mück
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia Solutions and Networks Oy
Original Assignee
Nokia Solutions and Networks Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to EP20070010645 priority Critical patent/EP1998465A1/en
Priority to EP07010645 priority
Priority to EP07010645.5 priority
Application filed by Nokia Solutions and Networks Oy filed Critical Nokia Solutions and Networks Oy
Priority to PCT/EP2008/055969 priority patent/WO2008145535A1/en
Publication of US20100135374A1 publication Critical patent/US20100135374A1/en
Assigned to NOKIA SIEMENS NETWORKS OY reassignment NOKIA SIEMENS NETWORKS OY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KOZEK, WERNER, MUECK, JOSEF
Application granted granted Critical
Publication of US8300519B2 publication Critical patent/US8300519B2/en
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M3/00Automatic or semi-automatic exchanges
    • H04M3/22Supervisory, monitoring, management, i.e. operation, administration, maintenance or testing arrangements
    • H04M3/26Supervisory, monitoring, management, i.e. operation, administration, maintenance or testing arrangements with means for applying test signals or for measuring
    • H04M3/28Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
    • H04M3/30Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop
    • H04M3/302Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop using modulation techniques for copper pairs
    • H04M3/304Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop using modulation techniques for copper pairs and using xDSL modems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B3/00Line transmission systems
    • H04B3/02Details
    • H04B3/46Monitoring; Testing
    • H04B3/487Testing crosstalk effects
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M3/00Automatic or semi-automatic exchanges
    • H04M3/22Supervisory, monitoring, management, i.e. operation, administration, maintenance or testing arrangements
    • H04M3/26Supervisory, monitoring, management, i.e. operation, administration, maintenance or testing arrangements with means for applying test signals or for measuring
    • H04M3/34Testing for cross-talk

Abstract

A method and a device are provided for crosstalk evaluation of a channel, wherein the channel is represented and/or modeled by a multiple-input-multiple-output (MIMO) system connecting a first network component with at least one second network component. The MIMO system contains first coefficients associated with transmission lines that are in particular associated with crosstalk. The crosstalk contains a near-end crosstalk (NEXT) portion and a far-end crosstalk (FEXT) portion. The first network component sends a signal to one second network component; the far-end crosstalk portion and the near end crosstalk portion are evaluated.

Description

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a method and to a device for crosstalk evaluation and to a communication system comprising such a device.

DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network.

Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voice band modem can provide. Such fast transmission is achieved by utilizing frequencies that are normally not used by a voice telephone call, in particular, frequencies higher than normal human hearing.

VDSL (Very High Speed DSL) is an xDSL technology providing faster data transmission over a single twisted pair of wires. High bit rates are achieved at a range of about 300 meters (1000 ft), which allows for 26 Mbit/s with symmetric access or up to 52 Mbit/s in downstream-12 Mbit/s in upstream with asymmetric access.

Currently, standard VDSL uses up to 4 different frequency bands, two for upstream (from the client to the telecom provider) and two for downstream. Suitable modulation techniques are QAM (quadrature amplitude modulation) or DMT (discrete multitone modulation).

According to its high bandwidth, VDSL is capable of supporting applications like HDTV, as well as telephone services (e.g., Voice over IP) and general Internet access, over a single connection.

VDSL2 (Very High Speed Digital Subscriber Line 2) is an access technology that exploits the existing infrastructure of copper wires that were originally used for plain old telephone service (POTS). It can be deployed from central offices, from fiber-fed cabinets preferably located near the customer premises, or within buildings.

VDSL2 is designed to support the wide deployment of Triple Play services such as voice, video, data, high definition television (HDTV) and interactive gaming. VDSL2 enables operators and carriers to gradually, flexibly, and cost efficiently upgrade existing xDSL infrastructure.

ITU-T G.993.2 (VDSL2) is an enhancement to G.993.1 (VDSL) that permits the transmission of asymmetric and symmetric (full duplex) aggregate data rates up to 200 Mbit/s on twisted pairs using a bandwidth up to 30 MHz.

The xDSL wide band modulation approaches are problematic relating to crosstalk interference that is introduced to the twisted pair transmission line and received by the modem.

Crosstalk occurs when wires are coupled, in particular between wire pairs of the same or a nearby bundle that are used for separate signal transmission. Hence, data signals from one or more sources can be superimposed on and contaminate a data signal. The crosstalk comprises a near-end crosstalk (NEXT) and a far-end crosstalk (FEXT).

Based on such crosstalk, data signals transmitted over twisted-pair lines can be considerably degraded by the crosstalk interference generated on one or more adjacent twisted-pair phone lines in the same and/or a nearby multi-core cable or bundle. With an increasing transmission speed, this problem even deteriorates, which may significantly limit a maximum data rate to be transmitted via a single line.

A multiple-input-multiple-output system (hereinafter referred to as MIMO system) is of significant importance in modern communication technology. Such MIMO system allows to model crosstalk interference of a telecommunication system.

Methods for single ended line testing (SELT) are used in DSL environments to ensure operation of such system. Such SELT-method is, e.g., able to recognize a line failure (interruption of a path or loop) within a main distribution unit without additional measurement equipment required.

BRIEF SUMMARY OF THE INVENTION

The object to be solved is to transfer the principles of single ended line testing to the MIMO system.

This problem is solved according to the features of the independent claims. Further embodiments result from the depending claims.

In order to overcome this problem a method is provided for crosstalk evaluation of a channel, wherein the channel is represented and/or modeled by a multiple-input-multiple-output (MIMO) system connecting a first network component with at least one second network component. The MIMO system comprises first coefficients associated with transmission lines that are in particular associated with crosstalk, wherein said crosstalk comprises a near-end crosstalk (NEXT) portion and a far-end crosstalk (FEXT) portion. The method comprises the steps:

    • the first network component sends a signal to one second network component;
    • the far-end crosstalk portion and the near end crosstalk portion are evaluated.

It is an embodiment that the signal sent by the first network component is a signal of a predetermined power density, in particular a maximum power density regarding the particular line or connection.

Hence, the approach allows to perform a single ended line testing by utilizing crosstalk, thereby determining whether a particular line between the first network component and one of the second network components is broken down.

In another embodiment, a response to the signal sent by the first network component is measured on at least one line connecting the first network component and one second network component.

According to the signal a crosstalk may be induced to at least one of the other (adjacent) lines. As the signal is known, this crosstalk can be evaluated in order to determine whether a line between, e.g., a port of the first network component and a particular second network component is interrupted.

In yet another embodiment, a pulse response based on the signal of the predetermined power density is evaluated.

It is a further embodiment that the far-end crosstalk portion and the near-end crosstalk portion are separated from one another.

Hence, determining the far-end crosstalk portion allows to assess whether the line to the particular second network component is valid.

It is a further embodiment that the near-end crosstalk portion and the far-end crosstalk portion are evaluated according to equation
H eff,k,l =H next,k,ll ·H fext,k,l ·H l
wherein

    • Hnext,k,l refers to a near-end crosstalk (NEXT) transfer function;
    • Hfext,k,l refers to a far-end crosstalk (FEXT) transfer function;
    • α1 refers to a complex reflection coefficient of the inactive customer-premises equipment (CPE);
    • Hl refers to a transfer function of a loop l.

The far-end crosstalk function can be assessed according to

H fext , k , l = T long ( H eff , k , l ) α l · H l .

Further, the linear operation Tlong(Heff,k,l) can be described in a time domain, thereby multiplying a time domain impulse response heff,k,l (i.e., the Fourier transformation of Heff,k,l) with a rectangular window function pτ(t):

( T long ( H eff , k , l ) ) ( f ) = def F t f ( p τ ( t ) h eff , k , l ( t ) ) ,
wherein

    • Ft
      Figure US08300519-20121030-P00001
      f represents the Fourier transformation (to be processed preferably via an FFT-algorithm);
    • pτ(t) is to be selected such that portions comprising a group delay that is smaller than the group delay of port l are set to 0.

It is also an embodiment that (at least a portion of) alien crosstalk can be determined by averaging a disturbance in a time domain and/or in a frequency domain.

In a next embodiment, the alien crosstalk is evaluated by a method comprising the steps:

    • a signal-to-noise ratio is correlated across ports that are used for SELT evaluation; and
    • the disturbance is identified in a power density spectrum and/or in timely sequence.

The signal-to-noise ratio (SNR) is processed across several ports of the first network component that may be used for SELT evaluation purposes. The disturbance caused by the alien crosstalk may then be assessed and/or identified within a power density spectrum and/or within a timely sequence.

In another embodiment, at least one of the second network components is running in a low-power mode. Such low-power mode may correspond to a L2-Mode according to an xDSL specification.

It is yet a further embodiment that the first network component is a Central Office (CO) or a Digital Subscriber Line Access Multiplexer (DSLAM).

It is an embodiment that the at least one second network component is a customer-premises equipment (CPE) each.

In yet another embodiment the at least on second network component is off and/or disconnected.

In particular, one of the second network components may be off and/or disconnected. In such case, the connection (line) between the first network component and this second network component may be used for evaluating crosstalk portions (NEXT and FEXT) caused by the signal sent from the first network component (via another line to another second network component).

It is also an embodiment that the far-end crosstalk exceeds a predetermined threshold in order to be evaluated. Otherwise, it may not be regarded as far-end crosstalk.

In a next embodiment, the crosstalk evaluated is used to identify at least one auxiliary path of the MIMO system.

Further, the pulse response evaluated may be used to identify an interruption of a line or connection between the first network component and one second network component.

In an embodiment, the method provided herein may be used in an xDSL environment as well as in an Ethernet environment.

The method may also be used for single ended line testing that is in particular initiated by the first network component.

The problem state supra is also solved by a device for crosstalk evaluation comprising a processor unit that is arranged and/or equipped such that the method as described herein is executable on said processor.

It is an embodiment that said device is a communication device, in particular a Central Office (CO) or a Digital Subscriber Line Access Multiplexer (DSLAM).

The problem is also solve by a communication system comprising said device as describe herein.

Embodiments of the invention are shown and illustrated in the following figures:

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 shows a multiple-input-multiple-output (MIMO) system modeling near end crosstalk (NEXT) and far end crosstalk (FEXT);

FIG. 2 shows a graph comprising a central office (CO) with several ports (CO1, CO2, . . . , COn) that are connected to a customer-premises equipment (CPE1, CPE2, . . . , CPEn) each;

FIG. 3 shows a flowchart comprising steps of a method to evaluate crosstalk and the perform single ended line testing via such crosstalk interference identified;

FIG. 4 shows a scenario comprising a communication network allowing to send data from a server to a client in particular via an xDSL connection.

DESCRIPTION OF THE INVENTION

FIG. 1 shows a multiple-input-multiple-output (MIMO) system modeling near end crosstalk (NEXT) and far end crosstalk (FEXT). The Loop Plant Model LPM represents the complete channel structure including (but not limited to) a main distribution frame, optional branching devices and crosstalk interferences of various kind.

Advantageously, such Loop Plant Model LPM can be used to model upstream (from a customer-premises equipment CPE to a central office CO) and downstream (traffic from the CO towards the CPE) traffic via separate ports.

Further, the Loop Plant Model LPM comprises a matrix of pulse responses comprising pulse responses of the transmission lines in its diagonal and crosstalk interference outside of the matrix′ diagonal:

y k ( t ) = l = 0 L - 1 ( h k , l * x l ) ( t ) , ( 1 )
wherein hk,k(t) is associated with the respective transmission line and hence represents the pulse response of said transmission line and hk,l(t) (k≠l) represents the crosstalk interference outside of the matrix′ diagonal, i.e. crosstalk interference between a port with an index k and another port with an index l.

It is to be noted that the symbol * expresses a convolution operation.

An actual port thus comprises two virtual ports, one port in upstream direction and another port in downstream direction. This allows to capture SELF-NEXT (i.e., a single ended line testing near-end crosstalk between upstream and downstream of the same physical port) in a compact model.

The approach presented herein could be advantageously used as a extension to an SELT measuring principle.

It is noted that such SELT measurement is subject to ITU-T, Study Group 15. The earlier project “G.selt” is migrated into a project “G.lt”. Details regarding SELT may be obtained from document NC-U09R1 of ITU Study Group 15.

Hence, not only the main paths of the MIMO system, but also the auxiliary (diagonal) paths are identified. This is advantageously if

    • a) at least one customer-premises equipment is switched off or not active; and
    • b) the far-end crosstalk portion exceeds a predetermined threshold.

In FIG. 2, a MIMO-SELT path from a port CO1 of a central office to a customer-premises equipment CPE1, an idle path from a port CO2 of the central office to a customer-premises equipment CPE2 and a SHOWTIME (i.e. “active”) path from a port COn of the central office to a customer-premises equipment CPEn are shown.

As the connection between the port CO1 and the customer-premises equipment CPE1 is active, a signal, preferably a pseudo-random signal with a maximum admissible power density is initiated by the central office (via its port CO1). The customer-premises equipment CPE2 is not active, e.g., switched off. The associated port CO2 at the central office is set to a listening state. The path n (also referred to as loop n) between the port COn and the customer-premises equipment CPEn is active, data is exchanged via that loop, both terminals are in a SHOWTIME state. Hence, only limited changes due to the signal initiated via the port CO1 could be determined at the port COn.

Steps for evaluating crosstalk, in particular in order to determine whether or not a loop or path of the MIMO system is interrupted, could be performed either at the central office (in particular within a transceiver chipset of the central office) and/or offline at a network management system.

It is a particular advantage that the method provided fulfills a real-time requirements of the event-synchronization between sending the signal via port CO1 and receiving at port CO2.

A frequency transfer function Heff,k,l between a transmitting port k and a receiving (listening) port l can be described as:
H eff,k,l =H next,k,l+α l ·H fext,k,l ·H l  (2),
wherein

    • Hnext,k,l refers to a near-end crosstalk (NEXT) transfer function;
    • Hfext,k,l refers to a far-end crosstalk (FEXT) transfer function;
    • αl refers to a complex reflection coefficient of the inactive customer-premises equipment (CPE);
    • Hl refers to a transfer function of a loop l.

The complex reflection coefficient αl as well as the transfer function Hl of loop l can result from a conventional SELT test method.

Subsequently, the near-end crosstalk portion and the far-end crosstalk portion need to be separated from one another.

This can be achieved by utilizing the fact that the near-end crosstalk portion has a reduced runtime due to its limited propagation:

H fext , k , l = T long ( H eff , k , l ) α l · H l , ( 3 )
wherein the linear operation Tlong(Heff,k,l) can be described in a time domain, thereby multiplying a time domain impulse response heff,k,l (i.e., the Fourier transformation of Heff,k,l) with a rectangular window function pτ(t):

( T long ( H eff , k , l ) ) ( f ) = def F t f ( p τ ( t ) h eff , k , l ( t ) ) , ( 4 )
wherein

    • Ft
      Figure US08300519-20121030-P00001
      f represents the Fourier transformation (to be processed preferably via an FFT-algorithm);
    • pτ(t) is to be selected such that portions comprising a group delay that is smaller than the group delay of port l are set to 0.

The group delay can be derived from Hl by means of a Fourier transformation.

Regarding the numerical stability of equation (3) it is noted that in particular with regard to long lines or loops a regularization is deemed advantageously. This encounters the fact that an estimation accuracy of Hfext,k,l will decrease with an increasing frequency.

In addition to a detection of crosstalk based on signals generated inside the MIMO system (also referred to as “alien crosstalk”), it is also possible to identify crosstalk based on disturbances from outside the MIMO system, e.g., a disturbance based on electromagnetic interspersion.

In case of alien crosstalk, an averaging of such disturbance is performed in a time domain and/or in a frequency domain, in particular because of the small pattern of the DMT symbol rates in the time domain and because of the small pattern of the subcarrier spacing in the frequency domain.

Hence, the signal-to-noise ratio is correlated across the ports (available for SELT evaluation), an alien disturbance may be identified in a power density spectrum and/or in timely sequence (switching performance).

It is further possible to perform SELT not only in cases when there is no customer-premises equipment connected (or switched off), but also when it is in a low-power mode (e.g., L2-Mode according to particular xDSL specifications).

The approach presented herein can be applied to various kinds of networks connecting different network components or network elements. The connection can be of xDSL type and/or of non-xDSL type. In can in particular be used for multi-core connections between network components, e.g., in Ethernet environments.

FIG. 3 shows a flowchart comprising steps of a method to evaluate crosstalk and the perform single ended line testing via such crosstalk interference identified.

In a step 301, the first network component sends a signal of a predetermined power density to one second network via a particular line or connection. Preferably, the first network component is a central office comprising several ports to each of which a customer-premises equipment can be connected (according to the graph of FIG. 2).

Pursuant to signal sent in the step 301, the first network component in a step 302 listens to a crosstalk response induced to another line connecting another port of the central office with another customer-premises equipment. Preferably, the customer-premises equipment attached to this line is inactive or in particular switched off.

The far-end crosstalk portion and the near-end crosstalk portion are separated in a step 303. Such processing can be performed, e.g., within the central office or offline within a network management entity.

In a step 304, based on the processed and evaluated crosstalk portions, a connectivity of a further line connecting a further port of the central office with a further customer-premises equipment can be checked.

Hence, according to the steps provided, a single ended line test of adjacent lines can be performed by the central office (or by a digital subscriber line access multiplexer) utilizing crosstalk interference to such adjacent lines.

A particular scenario of a communication network is shown in FIG. 4. Downstream Traffic is conveyed from the Server via a Network to a Central Office or Digital Subscriber Line Access Multiplexer CO/DSLAM. The CO/DSLAM is further connected via a digital subscriber line xDSL to a Customer-Premises Equipment CPE. The digital subscriber line connection can be in particular of the following type:

    • Asymmetric Digital Subscriber Line ADSL, ADSL2, ADSL2+;
    • High Data Rate Digital Subscriber Line HDSL;
    • Very High Speed Digital Subscriber Line VDSL, VDSL2.

The customer can be connected to the Customer-Premises Equipment CPE via a set-top box and a television or via a personal computer PC/TV. Data that is sent from the PC/TV towards the Server is referred to as Upstream Traffic.

Preferably, an operator or provider wants to efficiently use the xDSL downstream direction from the CO/DSLAM to the CPE by employing high data rate with low crosstalk effects.

Claims (21)

1. A method for crosstalk evaluation of a channel, the channel being represented by a multiple-input-multiple-output (MIMO) system connecting a first network component with at least one second network component, the MIMO system including first coefficients associated with transmission lines and second coefficients associated with crosstalk, wherein the crosstalk contains a far-end crosstalk portion and a near-end crosstalk portion, the method comprises the steps of:
sending, via the first network component, a signal of a predetermined power density to one of second network components; and
evaluating the far-end crosstalk portion and the near end crosstalk portion according to equation:
H eff , k , l = H next , k , l + α l · H fext , k , l · H l with H fext , k , l = T long ( H eff , k , l ) α l · H l
wherein:
Hfext,k,l is a far-end crosstalk portion,
Hnext,k,l is a near-end crosstalk portion
Heff,k,l is a transfer function between a transmitting port k and a receiving port l,
Hl is a transfer function of a loop l,
αl is a complex reflection coefficient, and
Tlong is a linear operation utilizing a fact that the near-end crosstalk portion has a reduced runtime due to its limited propagation.
2. The method according to claim 1, which further comprises measuring a response to the signal sent by the first network component on at least one line connecting the first network component and the one second network component.
3. The method according to claim 1, which further comprises evaluating a pulse response based on the signal.
4. The method according to claim 1, which further comprises separating the far-end crosstalk portion and the near-end crosstalk portion.
5. The method according to claim 1, wherein a linear operation:
H fext , k , l = T long ( H eff , k , l ) α l · H l
can be referred to as:
( T long ( H eff , k , l ) ) ( f ) = def F t f ( p τ ( t ) h eff , k , l ( t ) )
wherein pT(t) is a rectangular window function pT(t), and heff,k,l is a time domain impulse response.
6. The method according to claim 1, which further comprises determining alien crosstalk by averaging a disturbance in at least one of a time domain and a frequency domain.
7. The method according to claim 6, which further comprises the steps of:
correlating a signal-to-noise ratio across ports that are used for single ended line testing (SELT) evaluation; and
identifying a disturbance in at least one of a power density spectrum and a timely sequence.
8. The method according to claim 1, wherein at least one second network component is running in a low-power mode.
9. The method according to claim 8, wherein the low-power mode corresponds to an L2-Mode according to an xDSL specification.
10. The method according to claim 1, wherein the first network component is one of a Central Office and a Digital Subscriber Line Access Multiplexer.
11. The method according to claim 1, wherein the at least one second network component is customer-premises equipment.
12. The method according to claim 1, wherein at least one of the second network components is at least one of off and disconnected.
13. The method according to claim 1, wherein the far-end crosstalk exceeds a predetermined threshold.
14. The method according to claim 1, wherein the crosstalk evaluated is used to identify at least one auxiliary path of the MIMO system.
15. The method according to claim 1, which further comprises using an evaluated pulse response to identify an interruption of a line.
16. The method according to claim 1, which further comprises performing the method in at least one of an xDSL environment and an Ethernet environment.
17. The method according to claim 1, which further comprises performing the method for single ended line testing initiated by the first network component.
18. A device for crosstalk evaluation, comprising:
a processor unit programmed to:
send, via a first network component, a signal of a predetermined power density to one of second network components; and
evaluate a far-end crosstalk portion and a near end crosstalk portion according to equation:

H eff,k,l =H next,k,ll·H fext,k,l·H l
with

H fext,k,l =T long(H eff,k.l)/αl ·H l
wherein:
Hfext,k,l is a far-end crosstalk portion,
Hnext,k,l is a near-end crosstalk portion
Heff,k,l is a transfer function between a transmitting port k and a receiving port l,
Hl is a transfer function of a loop l,
αl is a complex reflection coefficient and
Tlong is a linear operation utilizing a fact that the near-end crosstalk portion has a reduced runtime due to its limited propagation.
19. The device according to claim 18, wherein the device is a communication device.
20. The device according to claim 18, wherein the device is a communication device selected from the group consisting of a Central Office and a Digital Subscriber Line Access Multiplexer.
21. A communication system, comprising:
a device for crosstalk evaluation having a processor unit programmed to:
send, via a first network component, a signal of a predetermined power density to one of second network components; and
evaluate a far-end crosstalk portion and a near end crosstalk portion according to equation:

H eff,k,l =H next,k,ll·H fext,k,l·H l
with

H fext,k,l =T long(H eff,k.k)/αl ·H l
wherein:
Hfext,k,l is a far-end crosstalk portion,
Hnext,k,l is a near-end crosstalk portion
Heff,k,l is a transfer function between a transmitting port k and a receiving port l,
Hl is a transfer function of a loop l,
αl is a complex reflection coefficient, and
Tlong is a linear operation utilizing a fact that the near-end crosstalk portion has a reduced runtime due to its limited propagation.
US12/602,253 2007-05-29 2008-05-15 Method and device for crosstalk evaluation and communication system comprising such device Active 2029-01-06 US8300519B2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP20070010645 EP1998465A1 (en) 2007-05-29 2007-05-29 Method and device for crosstalk evaluation and communication system comprising such device
EP07010645 2007-05-29
EP07010645.5 2007-05-29
PCT/EP2008/055969 WO2008145535A1 (en) 2007-05-29 2008-05-15 Method and device for crosstalk evaluation and communication system comprising such device

Publications (2)

Publication Number Publication Date
US20100135374A1 US20100135374A1 (en) 2010-06-03
US8300519B2 true US8300519B2 (en) 2012-10-30

Family

ID=38617946

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/602,253 Active 2029-01-06 US8300519B2 (en) 2007-05-29 2008-05-15 Method and device for crosstalk evaluation and communication system comprising such device

Country Status (5)

Country Link
US (1) US8300519B2 (en)
EP (2) EP1998465A1 (en)
CN (1) CN101772900B (en)
AT (1) AT523972T (en)
WO (1) WO2008145535A1 (en)

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8341574B2 (en) * 2009-03-06 2012-12-25 Synopsys, Inc. Crosstalk time-delay analysis using random variables
US8767521B2 (en) * 2009-09-08 2014-07-01 Ikanos Communications Inc. Method and apparatus for crosstalk cancellation during SELT testing
CN102668393B (en) 2009-10-30 2016-03-23 瑞典爱立信有限公司 For equipment and the method for the single-ended estimate of far-end cross talk in digital subscriber line
EP2388983B1 (en) * 2010-05-18 2012-12-19 Alcatel Lucent Method for testing a component of a vectoring system and line termination equipment configured to carry out said method
WO2012167439A1 (en) * 2011-06-10 2012-12-13 华为技术有限公司 Method, appratus and communication device for signal transmission to measure lines
CN104641567B (en) * 2013-09-17 2016-08-17 华为技术有限公司 A kind of disturbing line detection method, Apparatus and system
US9337893B2 (en) * 2013-12-10 2016-05-10 Qualcomm Incorporated Crosstalk analysis methods using superposition
CN108649996A (en) * 2014-03-03 2018-10-12 领特公司 Line simulators
CN106716853A (en) * 2014-09-30 2017-05-24 瑞典爱立信有限公司 Method and arrangement in a DSL vectoring system
US10735048B1 (en) * 2014-12-05 2020-08-04 Marvell Asia Pte, LTD Network switch apparatus and methods for global alien crosstalk characterization, diagnostics and network optimization
WO2016101241A1 (en) * 2014-12-26 2016-06-30 华为技术有限公司 Signal acquiring method, device and system
WO2017164788A1 (en) * 2016-03-24 2017-09-28 Telefonaktiebolaget Lm Ericsson (Publ) Method and system for estimating crosstalk between electrical transmission lines
CN107305229B (en) * 2016-04-22 2020-08-14 迈普通信技术股份有限公司 Method and device for evaluating quality of passive link
CN106027120B (en) * 2016-05-13 2018-05-08 南京航空航天大学 A kind of method for eliminating multi-conductor transmission lines near-end stable state crosstalk
US10873365B1 (en) 2016-08-04 2020-12-22 Marvell Asia Pte., Ltd. Alien crosstalk cancellation for a multiport ethernet system
EP3504803A1 (en) * 2016-08-29 2019-07-03 British Telecommunications Public Limited Company Method and apparatus for transmitting data over metallic wire pairs
CN107920037B (en) * 2016-10-10 2021-01-12 上海诺基亚贝尔股份有限公司 Optical communication method and apparatus
GB2573906B (en) * 2016-12-28 2020-04-15 Sckipio Tech S I Ltd System and method unifying linear and nonlinear precoding for transceiving data
CN109217953A (en) * 2018-09-26 2019-01-15 郑州云海信息技术有限公司 A kind of noise-reduction method and system based on analysis channel signal-to-noise ratio

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6538451B1 (en) 1999-06-25 2003-03-25 Telcordia Technologies, Inc. Single ended measurement method and system for determining subscriber loop make up
US20030190000A1 (en) * 1998-04-10 2003-10-09 Wataru Matsumoto Digital communication device
US20050195892A1 (en) 2004-03-05 2005-09-08 Texas Instruments Incorporated Training and updating for multiple input-output wireline communications
US6982560B2 (en) * 2003-07-18 2006-01-03 Agilent Technologies, Inc. Method and system for determining cross-talk effects
US6985521B1 (en) 2000-01-07 2006-01-10 Ikanos Communication, Inc Method and apparatus for channel estimation for X-DSL communications
US20070083339A1 (en) * 2005-09-29 2007-04-12 Sawyer T S Broadband differential coupling devices, systems and methods
US20070108989A1 (en) * 2005-10-28 2007-05-17 Huawei Technologies Co., Ltd. Method and apparatus for time domain reflection test of transmission line
US20070121715A1 (en) * 2005-11-30 2007-05-31 Huawei Technologies Co., Ltd. Method and device for crosstalk test in multi-subscriber communication line
US20070133723A1 (en) * 2005-12-10 2007-06-14 Min-Ho Cheong Method and apparatus for cancellation of cross-talk signals using multi-dimensional coordination and vectored transmission
US20080031313A1 (en) * 2006-08-07 2008-02-07 Vladimir Oksman Performance stabilization for multi-carrier DSL
US20080285635A1 (en) * 2007-05-15 2008-11-20 Jin Wang Methods and apparatus to qualify a wire-pair for a digital subscriber line (dsl) service

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030190000A1 (en) * 1998-04-10 2003-10-09 Wataru Matsumoto Digital communication device
US6538451B1 (en) 1999-06-25 2003-03-25 Telcordia Technologies, Inc. Single ended measurement method and system for determining subscriber loop make up
US6985521B1 (en) 2000-01-07 2006-01-10 Ikanos Communication, Inc Method and apparatus for channel estimation for X-DSL communications
US6982560B2 (en) * 2003-07-18 2006-01-03 Agilent Technologies, Inc. Method and system for determining cross-talk effects
US20050195892A1 (en) 2004-03-05 2005-09-08 Texas Instruments Incorporated Training and updating for multiple input-output wireline communications
US20070083339A1 (en) * 2005-09-29 2007-04-12 Sawyer T S Broadband differential coupling devices, systems and methods
US20070108989A1 (en) * 2005-10-28 2007-05-17 Huawei Technologies Co., Ltd. Method and apparatus for time domain reflection test of transmission line
US20070121715A1 (en) * 2005-11-30 2007-05-31 Huawei Technologies Co., Ltd. Method and device for crosstalk test in multi-subscriber communication line
US20070133723A1 (en) * 2005-12-10 2007-06-14 Min-Ho Cheong Method and apparatus for cancellation of cross-talk signals using multi-dimensional coordination and vectored transmission
US20080031313A1 (en) * 2006-08-07 2008-02-07 Vladimir Oksman Performance stabilization for multi-carrier DSL
US20080285635A1 (en) * 2007-05-15 2008-11-20 Jin Wang Methods and apparatus to qualify a wire-pair for a digital subscriber line (dsl) service

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
ITU-T: "Very High Speed Digital Subscriber Line Transceivers 2 (VDSL2)", Serie G: Transmission Systems and Media, Digital Systems and Networks, G. 993.2, Feb. 2006.
ITU-T: "Very High Speed Digital Subscriber Line Transceivers", Series G: Transmission Systems and Media, Digital Systems and Networks, G.993.1, Jun. 2004.
ITU-Telecommunication Standardization Sector, "Updated Issues List for G.It",Temporary Document NC-U09R1, Study Group 15, Apr. 16-20, 2007, Napa Valley, California.
ITU—Telecommunication Standardization Sector, "Updated Issues List for G.It",Temporary Document NC-U09R1, Study Group 15, Apr. 16-20, 2007, Napa Valley, California.

Also Published As

Publication number Publication date
EP2153537A1 (en) 2010-02-17
AT523972T (en) 2011-09-15
EP1998465A1 (en) 2008-12-03
WO2008145535A1 (en) 2008-12-04
US20100135374A1 (en) 2010-06-03
CN101772900B (en) 2013-04-10
CN101772900A (en) 2010-07-07
EP2153537B1 (en) 2011-09-07

Similar Documents

Publication Publication Date Title
US8743937B2 (en) Systems and methods for characterizing transmission lines using broadband signals in a multi-carrier DSL environment
US7106833B2 (en) Automated system and method for management of digital subscriber lines
US8194767B2 (en) Systems and methods for MIMO precoding in an xDSL system
JP5057971B2 (en) Far end crosstalk determination system
US7242761B1 (en) System and method for determining the transmit power of a communication device operating on digital subscriber lines
US8477590B2 (en) Crosstalk identification for spectrum management in broadband telecommunications systems
KR100404240B1 (en) Method and system for estimating the ability of a subscriber loop to support broadband services
EP2278785B1 (en) High Speed Multiple Loop DSL System
US6470074B2 (en) System and method for providing data and voice services on a shared line
CN104350685B (en) The up DMT symbol of multiple circuits in alignment TDD DSL system
US20150350417A1 (en) Detection of wiring defects
US6633545B1 (en) System and method for determining the data rate capacity of digital subscriber lines
EP2356790B1 (en) Alien interference removal in vectored dsl
Oksman et al. The ITU-T's new G. vector standard proliferates 100 Mb/s DSL
US8767521B2 (en) Method and apparatus for crosstalk cancellation during SELT testing
Cook et al. The noise and crosstalk environment for ADSL and VDSL systems
JP5632535B2 (en) Transmission line testing for non-invasive diagnosis
US8908834B2 (en) Method, apparatus, and system for reducing digital subscriber line interference
US8854941B2 (en) Vectored DSL crosstalk cancellation
CN102318302B (en) Method, apparatus and system of signal processing
JP5216581B2 (en) DSL system training
US6999504B1 (en) System and method for canceling crosstalk
US6631120B1 (en) System and method for determining a communication protocol of a communication device operating on digital subscriber lines
US9398146B2 (en) System for diagnosing and optimizing vectored DSL lines
CN105191272B (en) The optimization of multiple circuits in warp-wise quantization system is trained using preparing to add group

Legal Events

Date Code Title Description
AS Assignment

Owner name: NOKIA SIEMENS NETWORKS OY, FINLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KOZEK, WERNER;MUECK, JOSEF;REEL/FRAME:028116/0596

Effective date: 20100107

STCF Information on status: patent grant

Free format text: PATENTED CASE

FPAY Fee payment

Year of fee payment: 4

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 8